1. Field of the Invention
The present invention relates to a method for surface treatment of a metal enclosure, and particularly to a method of surface treatment which protects an outer face of the enclosure from contamination, erosion and abrasion.
2. Related Art
Many different metallic materials such as steel and aluminum are widely used as enclosures for portable electronic apparatuses such as mobile phones and personal digital assistants (PDAs). Enclosures made of such materials are usually treated by way of electroplating to provide better surface features. However, a conventional electroplated coating formed on the surface of an enclosure is frequently not durable.
U.S. Pat. No. 5,783,313 discloses a coated article. The coating includes a combination of nickel and palladium layers. The article can have improved brightness and resistance to abrasion.
However, the coating is susceptible to fingerprint contamination. That is, fingerprints are easily formed and left on the coating. This adversely affects the aesthetic appearance of the article. Furthermore, the corrosion and wear resistance of the coating falls short of increasingly stringent requirements imposed by modern industrial standards.
Accordingly, an improved surface treatment of a metal enclosure which overcomes the above-mentioned problems is desired.
Accordingly, an object of the present invention is to provide a method for treating a metal enclosure which renders the enclosure fingerprint resistant.
Another object of the present invention is to provide a method for treating a metal enclosure which renders the enclosure resistant to corrosion and abrasion.
To achieve the above-mentioned objects, a method for treating a metal enclosure according to the present invention comprises the steps of: (a) sand-blasting the enclosure; (b) preheating the enclosure to a predetermined temperature, and putting the enclosure into the space in a vacuum chamber between two electrodes; (c) introducing reactive gases into the vacuum chamber, said reactive gases comprising 1,1,3,3-tetramethyldisiloxane and oxygen; and (d) applying high electrical power to the electrodes to cause the reactive gases to become an ionized plasma, said plasma reacting with a surface of the metal enclosure to form a layer of silicon oxide thereon. The layer of silicon oxide resists formation of a fingerprint when it is touched by a user.
Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment of the present invention with the attached drawings, in which: